Fuel Pressure gauge recommendations - Alfa Romeo Bulletin Board & Forums
 
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post #1 of 8 (permalink) Old 10-15-2018, 06:57 AM Thread Starter
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Fuel Pressure gauge recommendations

So I'm "fixing the fuel lines on my Weber converted '81 Spider. The PO actually had a return fuel line setup and I want to change it to the proper setup without a return, but I want to check the Fuel pressure to make sure it's a proper 3 PSI.

Does anyone have a recommendation for a good affordable Fuel pressure meter that will work with 8mm Alfa Fuel lines?

Also, where should I measure fuel pressure? Right before the carbs?

Many thanks,

GC

'81 Spider (Weber's, Euro Bumpers, Custom Interior) Ivorio over Red | '54 Austin Healey 100-4, Bone Stock save for M cam, Carmine over Black.
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post #2 of 8 (permalink) Old 10-15-2018, 08:13 AM
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Yes.... But first, I'd recommend you KEEP that return line!!

Reasons for loving a fuel return line:
1) Cooler fuel - flowing back to the tank means it isn't sitting there getting hot, at low throttle.
2) Pressure regulators LOVE flow - they have an easier job keeping pressure correctly at widely varying fuel flow demands
3) Pumps do not like being 'dead headed' - live longer healthier lives with constant flow.


All this is why modern cars have fuel loops!


Now - on the topic - measure and regulate at the carburetors. This gauge is working well for me : https://www.autozone.com/gauges-and-...ing/266125_0_0
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post #3 of 8 (permalink) Old 10-15-2018, 08:22 AM Thread Starter
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Fascinating...It's funny, I attended a car show with my Spider this weekend, and a number of Alfisti suggested that the line should be dead-headed...but Bruce your comments make a great deal of sense, plus by keeping the return line I wouldn't have the issue of having to cap the existing mental return line under the car.

I was looking for a temporary fuel pressure gauge - not one that is permanently installed...though I really like Bruces setup...

What should the fuel pressure be if running a return line? Still 3 PSI?

Many thanks,

GC

'81 Spider (Weber's, Euro Bumpers, Custom Interior) Ivorio over Red | '54 Austin Healey 100-4, Bone Stock save for M cam, Carmine over Black.
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post #4 of 8 (permalink) Old 10-15-2018, 09:24 AM
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Quote:
Originally Posted by Crowbar44 View Post
Fascinating...It's funny, I attended a car show with my Spider this weekend, and a number of Alfisti suggested that the line should be dead-headed...but Bruce your comments make a great deal of sense, plus by keeping the return line I wouldn't have the issue of having to cap the existing mental return line under the car.

I was looking for a temporary fuel pressure gauge - not one that is permanently installed...though I really like Bruces setup...

What should the fuel pressure be if running a return line? Still 3 PSI?

Many thanks,

GC
Yes, the PSI is the same - it's what Weber carbs want. You may want a slight restriction in the return line, to let the regulator work against (or the regulator might not be able to reach 3 PSI!!)

Originally, fuel lines were one-way, so the default seems to be "do it the old way"...

50 years from now - how are we going to restore a "classic" microprocessor based modern car?? Alfas - 1980 Spider, 1987 Milano, 1976 Spider
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post #5 of 8 (permalink) Old 10-15-2018, 09:48 AM
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I have been running a no-return fuel system on my Spider for at least 15 years. It is simple, fewer things to suspect if you are troubleshooting a problem. I have crewed for a few Alfa race cars with Webers and they do not use return lines. Some cheap regulators may need a return line but Filter King do not. Modern cars are using high pressure fuel systems that do require return lines.

Ed Prytherch
79 Spider
76 Suzuki GT500
2011 Jaguar XKR

A little government and a little luck are necessary in life, but only a fool trusts either of them. - P.J. O'Rourke
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post #6 of 8 (permalink) Old 10-15-2018, 10:21 AM Thread Starter
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For those who don't run a return fuel line, how do you cap the metal return line under the car? I was thinking a short run of flexible line with a threaded bolt in the end of the line...any other thoughts? I'd rather keep the metal return lines in case the next owner wants to convert back to SPICAs...

'81 Spider (Weber's, Euro Bumpers, Custom Interior) Ivorio over Red | '54 Austin Healey 100-4, Bone Stock save for M cam, Carmine over Black.

Last edited by Crowbar44; 10-15-2018 at 01:12 PM.
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post #7 of 8 (permalink) Old 11-01-2018, 04:23 PM
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We are running an '85 spider with Weber conversion, electric fuel pump, regulator and gauge installed between the two Webers. 2-3 psi. I have not installed a return line and appears I will not. Probably close the line off at the tank end with a plugged fuel line.
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post #8 of 8 (permalink) Old 11-01-2018, 08:16 PM
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Return line or not depends on the fuel pump. The click-click pumps don't need a return line while the buzzing pumps should have one-but it's not a big deal if they don't. Modern fuel injected cars do not have a return line, but there is a bypass at the pressure regulator in the fuel tank.
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